This application is directed toward power machines. More particularly, this application is directed toward drive systems for enabling power machines to move over a support surface. Power machines, for the purposes of this disclosure, include any type of machine that generates power for the purpose of accomplishing a particular task or a variety of tasks. One type of power machine is a work vehicle. Work vehicles are generally self-propelled vehicles that have a work device, such as a lift arm (although some work vehicles can have other work devices) that can be manipulated to perform a work function. Work vehicles include loaders, excavators, utility vehicles, tractors, and trenchers, to name a few examples.
Various power machines utilize hydraulic or hydrostatic drive systems that are powered by an engine. Such drive systems include one or more hydraulic pumps that selectively provide pressurized hydraulic fluid to one or more hydraulic travel motors to cause the power machine to move over a support surface. When pressurized hydraulic fluid is not being provided by the pumps to the drive motors in many of these power machines, the power machine is not capable of moving over a support surface. In some instances, such as when the power machine is being started, it may be advantageous to know whether hydraulic fluid is being provided to the drive motors. Some of these power machines also include brake mechanisms to reduce the speed of, or stop entirely, rotation of wheels that are coupled to drive motors even when at least some hydraulic fluid is being applied to the drive motors.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.